Typical mobile communication systems have been developed to provide voice services while guaranteeing user mobility. Such mobile communication systems have gradually expanded their coverage from voice services through data services up to high-speed data services. However, as current mobile communication systems suffer resource shortages and users demand even higher-speed services, development of more advanced mobile communication systems is needed.
In general, when reception from the serving cell becomes poor or a neighbor cell with reception signal strength higher than that of the serving cell is discovered, a user equipment (UE) performs handover to the neighbor cell.
Messages exchanged using radio resources during handover may include a handover command message and a handover confirm message. When such a handover related message is lost during handover, handover performance may be delayed. This may increase the service interruption time.
Particularly, in a heterogeneous network where multiple small cells are deployed in the coverage of a macro cell, handovers may occur more frequently, significantly increasing the frequency of failure in transmission and reception of handover related messages.
Hence, it is necessary to develop a method that enables more efficient transmission and reception of handover related messages.